Its been a while since I last posted a cannon so here we go. I managed to get hold of a Quick Exhaust Valve finally, seems their not very common in New Zealand.

I gave up trying to find some place to order one from so I went into town. Ebay was asking like 30 bucks for shipping, on top of a huge price, "are you having a laugh?"

I was directed to a place that specialized in hydraulic and pneumatic services and enquired about one. There were boxes of the things, and I was like "sweet."

The dude there gave me a good deal of $20 for a "3/8"inch one. I will go back and get a 3/4 inch or 1/2 inch one at a later date, probably for around 30-45$. This particular one is all steel and thats about all I know, it has no markings except for an arrow, don't know about the pressure rating but I took it up to 150psi and it seemed ok.

Now on to the gun. I didn't want to wait to next week to get fittings so I searched around for stuff that I could use at home. I had an old sodastream co2 canister so I used that as the main chamber, might be a bit small, buts its enough for now.

Luckily the thread was the right type and size so it connected nicely to the QEV. The opening in the cylinder isn't that big so I might drill it out at some stage to increase air flow.

I cobbled together some "Hanson" fittings that were lying around and the bits of my last cannon to make the charging and exhausting system. I know its too big for this size gun but its all I had. I managed to crack the ball valve case while screwing it on, piece of plastic crap. But I just used the other end that was ok and it works fine lol.

I didn't have any fittings for the barrel. I wrapped electrical tape around the end of the aluminum pipe that was to be the barrel until it was the right size to be screwed into the QEV. It actually screwed in quite tight and straight. I secured it with hot glue. I haven't had any problems with it so far, it doesn't leak at all, but Im just waiting till the projectile jams and the whole barrel blows off lol, but it should be right.

Like I said I've had it up to 150psi with no problems, the valve works good as and it keeps its pressure. I've been shooting bits of wooden dowel out of it and it seems to have a bit of power. Need to find something better then that though, something that will fly straight and have a bit of weight.

Specs. -Barrel length is 1meter and diameter is 10mm (internal). -Chamber volume I estimate to be around 400ml.

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Attachments

Close up of the barrel/QEV connection.

This is just a bit of dowel with a sharpened rod stuck into it and a squewer for a tail. I needed something that would fly straight because everything else I was firing would just hit the target sideways.

The sharpened rod after I pulled the dowel off. Its buried in there about 25mm and I couldn't pull it out, I tried.

Last edited by nz_cannons on Sat Oct 13, 2007 4:25 pm, edited 1 time in total.

Its not really a "shop" as such, its an engineering outfit that specializes in hydraulic and pneumatic equipment. These valves are used to speed up pneumatic rams (something like that) so thats why they had them in stock. There should be plenty of places in auckland that deal with these types of things, don't bother with Enzed because they only deal with hydraulic stuff. Just search the yellow pages for pneumatic services or something.

Just one note, this gun was more of a prototype then anything. My next one will have breech loading, bigger valves, bigger tanks, slim design, hopefully something that has accuracy and resembles a real rifle.

Right now im just trying to think of something to shoot out of the thing.

That is some really good tough work you are doing there bro.How do you just manage to find all the parts? I love that crap you got!!Yeah, keep up the good work

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